Amplifier Troubleshooting and Modification.

[@MrCarlsonsLab]

To learn about electronics in a different and "very effective" way, check out my Patreon electronics course here: www.patreon.com/MrCarlsonsLab

[@thatwasjustdumb]

have made mode of your super probes to sell?

[@psyolent.]

concur. highly recommend mr carlsons lab on patreon. paul teaches in a way i understand i have learnt orders of magnitude since following.

[@fourmula4812]

gg

[@gks6022]

I'm a retired EE, 40 years in power analog and RF. I have never seen anyone present electronics in the same manner that my grandfather taught me (and started a lifelong love) ...until seeing your videos. I am beyond impressed. Your series should be required coursework for undergrad engineers and trade schools. Well done, and thanks, I've re-learned a few old guy tricks.

[@seejayfrujay]

Yes, and yes, yes, yes. Not my grandfather, but an EE prof at the local university who was a ham radio operator.

[@rickgoebel6724]

The person who owns these amps is fortunate to have you as a friend to repair and upgrade them. We, the viewers, are fortunate to have you as our instructor to explain and show us how you did all of it. 10 thumbs up for this one.

[@MortenSundal]

I can't express how much I love watching these videos. You are like the Stephen Hawking of electronics. The way you explain complex (for a layman) circuits in a comprehensive and entertaining way, is unrivalled. You have me sitting through up to three hour long videos and enjoying every minute. Outstanding work.

[@volvo09]

Morten Sundal _ couldn't have said it any better! The video style and teaching style is awesome... Relaxing and super enjoyable. It goes so well with tube electronics. I have always had a happy fascination of them since young.

[@ttues]

I couldn't agree more, Morten. What a brilliant teacher! I know next to nothing about electronics theory, but he makes videos that are well thought out, intelligent and easy to follow for non-specialists.... Just incredible!

[@johnjacob757]

Yes, amazing videos. I spend hours watching them. I share them with my kids too. I want them to understand electronics.

[@grizzlybear7076]

I'm constantly amazed by your tremendous depth and understanding of electronics, from making coils, fixing parts, restorations, to even a desire to share your expertise in an entertaining way. Been a tech for almost 50 years, I sometimes feel like a beginner after watching your videos - you have re-inspired me! Thanks. Jon

[@ericjorgensen4826]

I especially like the long form of your videos where you go into great detail. I am an ex-broadcast technical guy (and extra class ham) from the 60's through the early part of the 21st century and appreciate your videos very much.

[@MrCarlsonsLab]

Thanks for you kind feedback Eric!

[@danielcummings8226]

Before you repair the second amp, please plug in a speaker to each so we can hear the difference in sound. Thanks, great videos!

[@gerryk3114]

I TRIED TO EXPLAIN TO MY FRIEND THAT RUNS SIX PACKS THAT THE HUM IS PART OF THE DESIGN AND THEIR IS NOTHING HE CAN DO EXTERNALLY TO REMEDY THE NOISE !! IT IS INHERENT IN THE DESIGN, SIMPLY BY THE PROXIMITY OF THE COMPONENTS !!! YOU HAVE VERY NICE INSTRUMENTATION !!! NICE TO HAVE SELF CONTAINED MATCHING LOADS IN YOUR MEASUREMENT EQUIPMENT !! I ALSO HAD A HARD TIME EXPLAINING THE BIAS RECOMMENDATION WAS ONLY TO GET YOU IN THE BALLPARK !!! THE ACTUAL BIAS WAS MUCH LOWER AND IS SET BY WATCHING THE CROSSOVER POINT ON THE OSCILLOSCOPE !!!

[@WV591]

every film by Mr C is auto thumbs up. what a gem of a channel.

[@MrCarlsonsLab]

Thanks for your kind comment!

[@blitzroehre1807]

A huge thumbs up to Mr. Carlson for taking the time and effort and his grand old Tektronix scope to fill us in for what this small capacitor in front of the choke (reactance) is for! Back at tech school many moons ago I asked the lecturer what this small value cap was for exactly, I had noted this feature in quite a few amp and radio schematics. His rather annoyed sounding answer was: Cant you see?? Its for quenching RF interference!! Can we get on with the lesson now?? I have built my fair share of amps and power supplies since then, always including this feature, a small HV cap, mostly 0,68 micro, always beleiving it was there to cut diode switching hash especially on the AM broadcast band. Now I know better, thanks to Mr Carlson :-) P.S. Concerning the Super Probe: Was not there once a little tube Signal tracer by Heathkit with a magic eye in the bottom corner that had a probe with a germanium diode in it which worked in a very similar manner? The model designation eludes me ATM... Best regards from Germany

[@australianbloke3934]

Inspiring videos. You have rekindled an undeveloped relationship with electronics from my youth. Now, at age 72, I have the time and the opportunity to continue my journey, not to mention keeping an active mind. During the last 3 years I have learned to speak a foreign language to a reasonable level of proficiency, now I will have to learn the French words for inductors, capacitors, valves, (tubes in your country I think) , current, voltage, impedance, resistance, capacitance, distortion, frequency, phase, etc etc etc. Subscribed and will look at your Patreon pages. Thank you.

[@kenchorney2724]

Great photography! Love the sharpness and brightness of the trace on old Tek scopes. Awesome improvement on the amps hum level.

[@volvo09]

Ken Chorney _ it even gives a nice pleasing effect on the camera at that scan rate.

[@sibsbubbles]

Interesting! I've seen some designs that feature a capacitor in front of the B+ choke (think it was 2.2uf or so on average) and a lot that do not (mostly Fender Twins of different eras), but didn't know what that was for. Now I do! Thank you again Paul! Please keep the videos coming! You are a great teacher and always can inspire me to both be better at teaching these sorts of things as well as implementing them for projects I wish to tackle as well.

[@FilipWahlberg]

A tip: Since these videos are so informative and useful for troubleshooting, they ought to be more searchable. If I come across a buzzy amplifier and haven't seen this video (at least not recently), I would suspect that Mr Carlson has the solution, but how to find the right video? So please add keywords to your video descriptions, even though they might be "spoilers". And think from a noob perspective so don't only mention "Crossover distortion" but also "fixing buzzing tube amplifier" and so on. I think that this will open up your channel to new fans!

[@vinceotten129]

I learned so much! Your practical demonstrations, both with the Carlson Super Probe and your older oscilloscope, taught me in ways I’ve never learned from a textbook. What a difference only a half a uF makes!

[@1959Berre]

Wow, that Tek scope trace ... what a beauty.

[@thomasdavis4253]

Is it bad I heard this phrase in Dave Jone's voice when I read it?

[@Roflcopter4b]

@@thomasdavis4253 I think the world would be a better place if all our internal monologues were in Dave's voice.

[@hiteck007]

You did an awesome job on those amps. So few techs have your skill level & valve amps are a bit tricky to work on too.

[@carpenter123154]

I find this trouble shooting video a valuable resource and a significant step towards my understanding of dampening inductor ringing. I'm amazed that a small cap can make, or break the noise threshold on an amplifier with an LC power supply filter. I appreciate the practical methodology employed in the experimentation process, and will use this process on my own designs.

[@khmr33]

I took your comment about bias circuits and applied it to my own troublesome guitar amp kit I built many years ago... Lo and behold one of the cheap bias pots was totally defective! I thought I'd finally figured it out. Amp worked for a few days then blew a mains fuse. After narrowing down some possibilities, I decided to go back from a tube rectifier to solid state and buy some new EL34's just to see if I get some different readings. The last time the mains fuse failed, it seemed to take the pilot light with it though... Now with all tubes and rectifier out, it fails the light bulb limiter test. Have I ruined the power transformer? The amp is no longer mission critical, I'm just going to buy a new Marshall, but it gives me time to strip this thing down and rewire it from scratch and do a better job. Eventually I'd like to use it out, but it's going to have to be absolutely reliable first. What's the best way to confirm the power transformer is definitely ruined?

[@abelzavala1303]

I like Mr Carlson working repair old radio and explain everything!

[@wechselrichterschaltungen]

Hello Mr. Carlsson, I think your c-l network works like a low-pass filter ..... it makes for the DC voltage almost no resistance, but for the 50/60 heart rest voltage from the rectifier a very big resistance. thanks for the great video. 73, from Germany

[@darkgreenambulance]

Hi, Walter - yes - the choke is particularly good and necessary in the larger amplifiers as it absorbs the "heart rest" as you put it, (nice expression - I like it!) without losing much overall voltage - evens things out. The capacitor`s storage also helps and takes some of the "strain" out of the chokes action. In the smaller amps, there is usually just a resistor between the caps. which wastes a bit, but works well enough with adequate capacitance - especially after the resistor.

[@moodyga40]

great video Mr Carlson the buzzing in the choke has always been a real paint for years, it been a balancing act to get rid of it. as you stipulate adding capacitance makes the voltage go up. i am too suprize how may tech forget about the peak voltages. i am building myself a 6V6 stereo amp at the moment. and now the choke issue has been resolved i have 2 PSU in my amp 1 for the left and one for the right and 2 x chokes love your videos keep them coming

[@tarlach1280x960]

Your a wizard... I so enjoy your clear and concise explanation of every detail of what your doing... Thanks again....

[@lambertax]

Thank you for the effort to make these videos with such quality. I really need that isolated probe.

[@PeteBasel]

Nice video, my dad was a radar tech in the Navy and he mentioned that a swing choke is designed to be driven from the rectifier without a cap and that it acted as a regulator if I am remembering correctly. It would be nice to have a clear discussion about that type of choke.

[@darkgreenambulance]

That`s an interesting account - I`m not qualified to comment, but I have seen amplifier circuits without a pre - choke capacitor. Most of them do seem to have them, though. Mullard used them in the "5-20" but not in the "5-10". That one just used capacitor - resistor - capacitor, both high value, (50uF!) but both amplifiers used limiting resistors after the rectifier - one on each anode out. I think the choke is desirable - especially in large amps, because it (obviously) smooths things out without incurring much voltage loss. As Mr Carlson showed, a relatively small cap, made a lot of difference - and, I would imagine - lessened the high amount of activity in that rather small choke. I`ve probably said too much!

[@darkgreenambulance]

Meant to say "one on each anode IN" ( between trans. and rectifier.)

[@codydowling1120]

BTW Paul, by measuring the time constant of the ringing, and then comparing that with an impedance plot of the capacitor, you can nearly eliminate the guess work by aligning the null in the impedance plot of the cap with the ringing of the signal. That said, the beauty of the method you show is in it's simplicity: There are only set positions of capacitors, and measuring them "in circuit" as you did ensures that any other parasitic elements and variations are captured in situ. Love your videos- very practical approach!

[@holywells]

Great information from a professional. By the way, I sure he hope doesn't live in earthquake country, and , if so, then I truly hope that all of that nice equipment is secured and strapped down so that it does not fall on either him or the floor when a tremor occurs!!

[@darkgreenambulance]

Crumbs - your right! Maybe a computer generated back-drop would be a better plan!

[@fredbach6039]

I loved your videos on the two audio 6-pack amplifiers especially the part about moving the b+ choke around for minimum hum at the speaker. I think an insulated magnetic shield plate might be very helpful. I have used these as a diagnostic tool kind of like you use your Carlson Super Probe capacitive pickup. I particularly enjoyed your fixing of the ringing by testing a variety of capacitors. Nice.

[@PINKFL0YD-s2h]

The Carlson superprobe?? My mind boggling, seriously great program. Love valve mono blocks and the transceivers you work on

[@MrCarlsonsLab]

Thanks Howard!

[@Chrissy4605]

Nice, I love how you came to the same conclusion, not one way but with two. Great way to show how things can be done with alternate methods.

[@richardross3815]

Wow.....that capacitance lesson was great.....well done. Thanks Paul

[@MrCarlsonsLab]

Glad you enjoyed Rick!

[@cubanpianoman]

Just letting you know that I appreciate your educational reviews, as I get to do a lot of cool stuff with your tips and tricks. Each of your videos is more useful than about a quarter semesters worth of circuit classes in my experience. Yeah, thanks

[@MrCarlsonsLab]

You're very welcome!

[@dave1135]

Great video, Paul. These newer units there's not much space to make any major changes. A fellow on another channel who does homesteading made a wood case to house a water pump and some fittings and valves including a timer. He did a very rough layout to give him ideas for the case size, but he forgot to take into account the pex lines he needed to plumb it. He made it fit, but it got ugly. You have to always think ahead. I'm sure the manufacturer spent much time planning parts layout for functionally as well as Aesthetics.

[@robertkibbler1564]

Don't understand much of it but still find it interesting to watch and learn something!... Thanx Paul...Rob

[@pierrelataillade7564]

Mr Carlson..... You are the man. The lab works provided here are top shelve. No dought. Even I can learn here.....

[@robertkibbler1564]

Don't understand much of it but still find it interesting to watch and learn something!... Rob.

[@raymondheath7668]

This was a very interesting project. I haven't worked on tube stuff since the late 60's and early 70's and most of those repairs were with a Sams photofact with no modifications. It looks like your super probe would still be a usefull tool in my shop with transistor amps

[@KentuckyRanger]

Glad to see the end to this project. What an awesome pair of amps! And after the tweaking, They're even better than before!

[@retrobrw919]

I always love watching your videos because I often learn things that are completely omitted through the modern electronics/electrical engineering university curriculum. I'm currently a junior in an EET(Electronics Engineering Technology) program at my state's university, and while we recently just covered RL, RC and RLC circuits, they don't really go into why we are learning all of it, or the applications for it.

[@MrCarlsonsLab]

I hope I can help fill in the holes for you.

[@jeffberwick]

Great debugging session! I'm interested in applying this to a 1950's 10W 6L6 Bell amp that has a hum issue.

[@TheRadioShop]

My comment vanished! Great job at nailing down that noise Paul. I really enjoyed this. Very nice presentation. I really have to get me an original Carlson's super probe.

[@MrCarlsonsLab]

Thanks for stopping by Buddy!

[@MaxKoschuh]

brilliant video. I've learned a lot. love the clear and bright Tektronix 547 CRT picture

[@MrCarlsonsLab]

I agree, nothing beats these old scopes for clarity.

[@Bass.Player]

Adding that cap worked out very good. I'm with you, if I found that noise present I would think that some components had been removed at some point.

[@davidportch8837]

I subscribe to quite a few channels Paul but yours is the only one that I watch all of the videos. Excellent video as always...

[@MrCarlsonsLab]

Thanks David, glad you are enjoying the video's!

[@patprop74]

Always enjoy learning and you teach well ,I don't plan on getting into the older tube stuff but I still enjoy learning form it. Thank you.

[@MichaelLloyd]

Thumbs up is not strong enough. We need a little SpaceX rocket symbol to click. Outstanding work Paul

[@MrCarlsonsLab]

Thanks Michael!

[@n2n8sda]

Just checked my late 30s / early 40s push pull AM radio (twin 42 outputs twin 76s for phase inversion) uses choke input off the 80 rectifier tube and has a .22uf 1000v cap in the same place you installed this one. I guess that is there for the same purpose (the choke on that radio is also quiet!)

[@MrCarlsonsLab]

Yes, Common Knowledge back then... I'm trying to teach these (what seems to be) forgotten ways now. Thanks for your comment!

[@n2n8sda]

Great video by the way, no doubt that it will save me a lot of troubleshooting as i'm in the middle of designing and builidng an all GT style MW/SW radio and even in the datasheet for the 5Y4 it doesn't mention ringing when using the tube in choke input configuration. Amazing how once common known things in many old trades become lost into secrecy through "progress." No idea how it's going to perform yet as I haven't sorted out coils / IF stage tranformers but out of the parts boxes i've settled initially with 6SK7's for RF preamp and IF amps, 6SA7, 6SQ7, 6V6GTs for PP and possibly a 6SN7 for phase inversion, oh as well I plan on using your little oscillator take off circuit to run a frequency counter :) The main goal of the build is to make something with low hum, pretty uncharacteristic for a table radio but it's something to do right, especially with some of the SW around here a lot of my radios have more hum than station on the weaker stations.

[@paulcalmond]

Mr Carlson's Lab Is this called a pi filter or is that different (high value capacitor before the reactor)

[@highpitwilma]

Only one word to describe this video,and all of Mr Carlson's other vids...BRILLIANT! Thanks a lot Buddy!! Cheers from Bill in Beautiful Northumbria in the UK.

[@MrCarlsonsLab]

Thank You for your kind comment Bill!

[@jonathanfadden9299]

You might want to try swapping the choke leads, reversing the phase of the magnetic radiation. Sometimes this makes a difference in coupling to other elements.

[@benbaselet2026]

Just in time for some Friday relaxation \o/

[@tedmoss]

Way back when I was a kid in 1959, I built a 10 Watt amp from scratch using 2 6V6 output tubes, it worked very well. I used an aluminum chassis with the holes punched out with a chassis punch, all done by hand. WA7VQR

[@Nephilim-81]

Incredible. So informative. I absolutely love this channel. 😊

[@jimkirk360]

Always on the edge of my seat waiting for the next video.

[@carloschafin1]

Ultra useful. What's great is these are things I'd love to experiment with, but usually just can't due to time so they remain unsolved or solved in a less elegant way. It's fascinating to watch you work through these gremlins. You're super probe is a great idea as well and I really do need to find the time to build one! I'm curious how quiet the choke and amp would have been in it's original position with the cap added? Also, I would have been tempted to use the 2.2uf and drop the bias back to the 180ma range. Xover looked good on the scope with that current setting. Thanks again for all you do!

[@MicheIIePucca]

I love your detailed explanations, and video quality compliments those. Always entertaining and always learning something from you. Thank you!

[@MrCarlsonsLab]

You're welcome Michelle!

[@denisohbrien]

wish you had shown the superprobe output with all capacitors, would have been interesting to hear the difference. fantastic video as always :)

[@abeleballestri612]

Very Interesting and tutorial way and method how to eliminate the drilling out of a transformer coupled to a voltage regulator circuit.thanks for the very nice method of troubleshooting

[@richardspiek1401]

Great job Mr. Carlson ! I'm watching your build of your NEW High Performance dipole for your new lab. Anxious to see how you raise that 30 ft. pole from ground. Hope you cover that in the future. Thanks again for sharing... N3JLR

[@MrCarlsonsLab]

You're very welcome Richard!

[@johnschlesinger2009]

Marvellous work, and everything explained with perfect clarity.

[@boblake2340]

Your capacitor fix is used often in switching power supplies, in a slightly different form. Its a snubber circuit or network. Usually a capacitor in series with a small value of resistance.

[@BruceNitroxpro]

Bob Lake, not QUITE the same fix, or problem. It is SIMILAR, because it does similar things but dumps the noise into a resistor instead of an inductor.

[@doctorjohn-burgtekie]

Thank you Mr Carlson for this excellent video and explanation. In the near future would you do a video explaining how you got started in electronics, any certifications and do you own your own company. I enjoy hearing about peoples experiences in electronics.

[@kingfishstacy]

Excellent videos. I've always been curious about electronics. And have wanted to build my own tube amp for years.

[@bitdiddle1]

I suspect that once you had traced the schematic, you saw that it was missing a filter capacitor on the output of the power rectifier and knew right away that would make trouble (i.e. the buzz in the resonator). The sharp points on the bottom of the full-wave rectifier output won't be supported by the inductance of the resonator. But still, a nice opportunity to show off the Carlson Superprobe! 73 de W1CMC

[@rillloudmother]

it is so satisfying when you connect the cap to ground and it goes silent!

[@lrodpeterson3046]

I'm curious if you know Dennis Had's story. He was Dentron, of some RF amplifier fame in the '70s/'80s, and he's still around. I understand he's quite accessible. I'm not suggesting you contact him and ask, "what were you thinking?", but a worthwhile conversation might ensue. This seems to me like a major improvement to his product, in which he might be interested.

[@lrodpeterson3046]

Huh. I didn't know that. Didn't he spin off AES from that, though? What I mean is, isn't that amp his design? Ironic, calling it AES. Being a ham, he might very well have been a customer of Amateur Electronic Supply (MKE, ORL, etc), almost universally known as AES. Again, ironically, they've been gone for a couple of years, now, too.

[@BruceNitroxpro]

@@lrodpeterson3046, good catch... sometime it's in the details, right? de KQ2E

[@j.w.8663]

www.sixpacs.com/tubetalk.shtml

[@bttrs]

Hello Mr Carlson, I am an electronics hobbyist and I really enjoy all your videos. I learn a lot about analog electronics each time but my knowledge is still mostly in digital electronics and computer science. Tube technology and point to point construction really fascinates me, I thought I might get myself on of those cheap sub 200$ Chinese tube amps from aliexpress or ebay to play around with, there are two SE designs, "6N9P+EL34-B" and "6P3P+6N8P". I believe the original designs are by a guy called "Siliconray", a electronics designer from china that used to make a lot of kits and designs base around tube amplifiers and he sold them on his website and the diyaudio forum, unfortunately he vanished some time ago and his website got hacked but you can still buy the kits. I wanted to ask if you think they are worth getting, also seeing you understand and improve those high end amps with ease makes me hopeful that these cheap amps might be a base for me to mod and improve. Thanks for all the amazing videos!

[@GeigerCounterVirtualMuseum]

Great way to head into the weekend.

[@graemebrumfitt6668]

Again great vid Paul, thanks for sharing. I think I need to man up as that arc would have had me jumping and running for cover. I truly love your restoration vids, the equipment you work on is breath taking so much nicer than the modern equivalent. Today I received in the post a lovely little Heathkit Daystrom AG-9U Audio Signal Generator "UK version" fell in love the moment I saw it :-) Again Mr C great vid n keep em coming. Regards G

[@faxcapper]

Snowing.....roads bad....perfect time for a Trouble Shooting Mr. Carlson video!!! :-)

[@W1RMD]

Thank you for your (again) awesome explanations! 🙌

[@tubedude226]

Very nice illustration of eliminating the ringing on the choke input filter, thank you! Could something similar be done to my Metcal MX-500 soldering station? It makes a very annoying buzzing noise, even unloaded. It does increase slightly when loaded.

[@ianmacdonald6350]

There will be a value at which the cap resonates with the inductor, and at that point the ringing will be significantly worse than with no cap. You need a value somewhat larger than that, as seen. Other thing, using a small electrolytic would not be wise because of the very large AC ripple at this point.

[@2010stoof]

I need to learn more about this stuff. Like really bad. I learned alot in high school. But seem to have forgotten in the last 20 years

[@dojmike]

I have some amps that claim to be "self biasing." The main one I refer to is the Leslie Organ Speaker Amp. When you get a chance, could you please explain the concept of "self biasing" vs the bias pots that are used on many guitar and other amps. Thanks for the fine videos.

[@rickg8015]

Great educational vid.. That choke’s most probably not designed for choke input duty.. I would replace those Solen metallized film too. They easily leak IME and is only rated at 85deg. But the worse part is how they sound. The Illinois Caps you use most probably sound better. I know they are not in coupling positions, but even as decouplers I am not a fan of them.

[@unknownsauce3768]

You should do some videos on cheap affordable tube amp builds using common components; start to finish. There is quite a selection of cheap tube amps on Chinese sites but reviews are scarce so perhaps a patron to buy a tweak one series? Would be a great series.

[@kenl2861]

Totally awesome. I’m really enjoying your videos, and learning TONS. Love the super probe. Wow. Your efforts here are very much appreciated!!!

[@MrCarlsonsLab]

Thank you very much Kenneth!

[@juanabreu5127]

Nice explanation, good teaching and high quality video. Thanks.

[@rebelba42]

Great sequel in this amp series. Nice to see your SuperProbe in action more often, this device is so useful I never want to miss it anymore! May I ask, did I misunderstand the BIAS current of about 160 mA to eleminate the cross over distortion in the last amp video? Because you have adjusted it to 220 mA this time. As always awesome video Paul, for me it comes as a bonus on a friday evening, many thanks for sharing!

[@MrCarlsonsLab]

Hi Ralf. For testing purpose, I just set it to the standard. When all is done, and both amps are back together, I will go over each and set them to an appropriate amount determined by the oscilloscope + appropriate safety margin. Thanks for your kind comment!

[@vadimagoshkov5540]

Hi Mr Carlson and thanks for your videos and sharing a knowledge! Regarding the bias... The higher current allows more Class A operation as I understand, so may be that's the reason for 220mA number? Although it's 220 for all 6, so each one will see less than 40mA with screen including. 400V * 0.04mA per tube = 16W (including screens). EL34 is rated for 25W. So why bother? ST70 calls for 55mA at ~450V B+ for example.

[@radu3g]

A power transformer which can double up to what it was designed ? That's a solid piece.

[@ShawnsterZR1]

Another awesome video! So, do you think moving the reactor was necessary since adding the caps reduced the noise level so drastically? Thank you for sharing your expertise and knowledge! Looking forward to the next video!!

[@HammerToneAmps]

Agree, I thought that would be the obvious first step once we saw the schematic.

[@sjhorton1184]

I understand your point Shawn, but suspect that it is always best to physically fix as much as possible before any electronic fix. Wondering if the cap value would have needed to be higher to shunt the higher level noise which would have created the higher B voltage that he wanted to avoid so as not to fry the audio output transformer?

[@harryalb8923]

wonderful, instructive and thorough work you are doing! Thanx!

[@bundylovess]

Nice job Paul you really are the man Big thumbs up

[@old64goat]

Real good video Paul, I never heard a filter choke called a reactor but when I think about it that is what it is...LOL

[@MrCarlsonsLab]

Thanks for stopping by Bill!

[@tymekrozanski123]

I dont get why some people dislike these vids

[@xeroeffect5745]

I reckon they watch them upside down and mistaken the dislike button for the like button. Either that or Mr Carlson's wife and her girlfriends are onto him ever since the breakup over the dining room makeover into Area 4. This is getting interesting.

[@orange70383]

Ego's and jealousy.

[@garybevis8691]

I find that people often dislike what they do not understand. I have a severe bromance for Mr. C, and watch every single video with more enjoyment than a Steven Spielberg movie. It's like he can speak and listen in RF and electrons. I hope to have 5% of his talent in electrical troubleshooting.

[@ethicalfarmer7424]

lol you need help :)

[@volvo09]

I hate to admit but sometimes my phone slides out of my hand when starting or changing videos and when going to comment on one. Sometimes my thumb hits dislike on a video by accident! I notice it and correct it, but I always wonder how many are mistakes! There's nothing to dislike! Except for being an angry person and disliking something rather than learning.

[@robinsonsoto8471]

You really an Excellent Eng.

[@RC-Flight]

Great video, I’m about to start a 6G15 tube reverb tank replica project that uses a choke just after the P.T. filtering capacitors can you be so kind as to do a video explaining the difference between reactors, inductors and chokes and there applications. It appears to me that they are the same piece of hardware, that preform different tasks. Glen in Ontario

[@heinzjung9378]

Very nice Work Mr.Carlson.

[@pedrojmorais]

Hi there, do you know what happened if you put small capacitors less than 0,1uF in all diodes? (Because the fix was to eliminate current noise from flowing through the coil, by eliminate before.) I'm just asking because it's a common filter practice to put them on high end audio equipment in order to filter diode on-off noise. Thanks for your channel!

[@theduckisok]

I love these videos. Learn a ton, and have been doing this for years.

[@JerryEricsson]

Just wondering, with the increasing availability of super caps, how would they work in amplifiers? The add where I recently picked up 6 6 farad super caps said they would be useful in getting better bass in amplifiers, but that seems a lot of capacitance even at the rated 2.7 volts.

[@JWH3]

Pulled some modest arcs at the 25 minute mark switching those caps in live, bet that keeps your focus sharp!

[@JWH3]

What's the backing material you're using for insulation there?

[@AlexLTDLX]

Fantastic video as always! I have a question and a video idea for you: I built a small S.E.T. amp (the Get Set Go), and when I added a volume pot to it, it outputs a buzz only at a specific volume level - about two thirds of the way up, if it matters. Any idea why? I understand a lot of people comment and ask questions; no worries if you can't get to this or it's not worthy of a video. Thanks!

[@drstrangelove09]

Excellent!! Thank you!!! 8:05 Did you not find with the scope that the bias should be smaller than what the manufacturer specified? What am I missing?

[@Kevin-cr9jt]

Awsume as always never fails to please with his videos !

[@nndorconnetnz]

Would you not get over 650V flat on the power cap till the cathodes warm up?

[@darkgreenambulance]

I would have thought so - using diodes instead of a valve rectifier - instant voltage - good point! Still, the caps themselves were rated for that if I recall - but you must be right!

[@Thomasp671]

Is there a way I can get a photo copy of the schematic (with the mods) that you drew up ! It's fantastic :-) Thanks

[@dizekat]

Have you tried wrapping some copper foil (soldered to itself to make a loop) around the reactor? Maybe with some Teflon to keep 600v off the foil. It should help a fair bit, the idea is that it will now be inducing current in that copper loop instead of other wires.

[@firststspeedway-hotwheelsr3545]

In the previous video , you showed how lowering the bias to 160 milliamps, you can get rid of the crossover distortion. Why then ,, do you set it to 220/230 milliamps? Is there something Im missing here?

[@dorelgogu8631]

I was wondering, if get rid of the ringing by adding the .47 micro caps, but leaving the reactor in his original place would also get the audio clean. Just a thought.